This second cycle of pontoons was cast in Aberdeen for the new 520 floating bridge.
The float-out process began Sunday afternoon, when crews opened small gates on the casting basin walls so water could begin entering the basin.
The pontoons will remain at the Port of Grays Harbor for inspections and will then be moored until needed for construction on Lake Washington.
Kiewit-General crews built the casting basin and will build 33 total bridge pontoons in Aberdeen as part of a $367.3 million design-build contract.
An additional 44 pontoons will be built in Tacoma under a separate contract. The floating bridge contract requires the new, six-lane SR 520 floating bridge to open to traffic by July 2015.
WSDOT is in negotiations with its contractors for pontoon issues encountered in spring 2012 and has not made an official determination on any potential schedule effects.
Project information is available here.